A MEASUREMENT OF THE SHAPE OF THE SOLAR DISK - THE SOLAR QUADRUPOLE-MOMENT, THE SOLAR OCTOPOLE MOMENT, AND THE ADVANCE OF PERIHELION OF THEPLANET MERCURY

The Solar Disk Sextant experiment has measured the solar angular diame ter for a variety of solar latitudes. Combined with solar surface angu lar rotation data, the solar quadrupole moment J(2) and the solar octo pole moment J(4) have been derived first by assuming constant internal angular rotation on cylinders and then by assuming constant internal angular rotation on cones. We have derived values of 1.8 x 10(-7) for J(2) and 9.8 x 10(-7) for J(4). We conclude with a discussion of error s and address the prediction of general relativity for the rate of adv ance of perihelion of the planet Mercury.